So what to do about Reston Town Center, suburban Fairfax County’s closest thing to the definition of a downtown? It offers more than 7,000 parking spaces in six garages and one surface lot. And all but a couple of hundred, in the Hyatt garage, are free.

Perhaps not for long.

Boston Properties Inc.’s near monopoly on the town center’s ownership, combined with the arrival of Metrorail in Reston, will likely herald the introduction of paid parking in one of the county’s most popular office and shopping destinations.

“I suspect that will happen sometime in the future, but there is no schedule, no rates established, no definitive timetable for that,” said Peter Johnston, Boston Properties senior vice president and D.C. regional manager. “If you think about it logically, it really is an urban environment in a suburban setting.”

Boston Properties owns roughly 1.5 million square feet in Reston, plus vacant land on either side of the Dulles Toll Road and a significant share of One and Two Fountain Square — the subject of a joint venture with the town center’s other major owner, Boston-based Beacon Capital Partners.

The demand for parking is certain to grow with the arrival of Metro’s Silver Line, first to Wiehle Avenue in late 2013 and then to Reston Town Center about four years later. While the new Wiehle Metro garage will include some 2,300 spaces, there are no new garages planned for the town center.

That means that by 2016, when Boston Properties is likely to own the 877,000-square-foot Fountain Square outright, it will control upward of 12,000 public parking spaces in Reston’s urban core — as demand from commuters, shoppers and visitors peaks.

The transition will likely start with commuter-related charges and eventually shift to paid parking for the center as a whole. It will be a “multistep process,” Johnston said.

Boston Properties officials broached the subject of paid parking during their second-quarter earnings call on Aug. 7. President Douglas Linde said the company expects to earn a 6 percent return on its $87 million investment in Fountain Square, though those numbers don’t reflect “future opportunities we have with regards to parking income.”

Boston Properties has already introduced gates in two of its Reston garages — those that back up to the Reston public transit center. The gate arms stay up until 10:30 a.m., when most commuters have already left their cars for the day.

The gates not only prevent commuters from overwhelming the garages but also serve as a means to “getting our customer base and the retail customers used to the prospect of coming in to a controlled environment as a precursor to being able to charge for parking,” Johnston said during the earnings call.

“First and foremost, this is about making sure we have the right parking for the tenants we have now,” he told the Washington Business Journal in a follow-up interview. “People driving in from Herndon and Oakton, we have to be able to prevent them from parking on our property and taking up spaces from our tenants.”

Mark Ingrao, CEO of the Greater Reston Chamber of Commerce, said he expects free parking will continue in the town center for the “foreseeable future.”

“Obviously, with the advent of rail, they’re going to have to analyze that,” Ingrao said.

But will paid parking scare the traditional suburban visitor away?

“I think people come here for the experience,” Ingrao said. “As president of the chamber, am I concerned about paid parking here? Sure. But I will qualify it by saying I don’t think it will be for the foreseeable future. And if it comes here, I think it will be more economic still to come here than it will be to go someplace like Tysons Corner.”

Boston Properties, Johnston said, will adjust parking rates “to what the market will bear.” He specifically cited Metro’s parking charges, which generally are $5 to $6 a day.

“The reality is, it doesn’t benefit us if we institute something that diminishes the overall quality of the experience of people coming to town center,” Johnston said.

But even the idea of paid parking is enough to generate angst among some retailers, who fear it will discourage shoppers and eat into their bottom lines.

“Reston Town Center is known as a great place not only to shop but to come and walk around with your pets, relax and grab a coffee or dinner,” said David Eisele, founder and CEO of Davelle Clothiers. “People who come here on a whim to hang out will likely go elsewhere because now they will stop and think about whether or not they want to pay for parking. With competitors offering free parking, my business will be negatively impacted by the decrease in foot traffic, and the popularity of the whole town center will suffer.”

Roughly 60,000 people live in Reston. And their daily needs are served by five nearby village centers, where parking will likely remain free, said Ken Knueven, president of the Reston Association. Knueven added that he is confident paid parking would not “hinder the attractiveness of Reston.”

“Given the advent of Metro cutting to Wiehle Avenue and eventually the Reston Parkway, I think we have to assume this is inevitable in the transportation corridor,” he said. “It’s a matter of working with commuters, residents and shoppers and trying to find a happy medium there.”